Like many states, Pennsylvania is planning many drunk driving checkpoints over the 4th of July holiday weekend. For an official list of the locations read this.

According to the posting, watch out for:

Chester County
July 2-4 DUI patrols along Routes 30, 100 and 113.

Montgomery County
July 2-6

DUI patrols along Route 611 in Abington and Upper Moreland townships.

DUI patrols on Routes 63, 202, 309, 463, 663 and Sumneytown Pike in Hatfield, Montgomery, Towamencin, Upper Gwynedd townships and Hatfield and Lansdale boroughs.

Franconia Township, Lower Salford Township, Hatfield Township, and the Upper Perkiomen Police

DUI patrols along Routes 1 and 30 in Lower Merion Township.
July 10
DUI checkpoint along Route 152 in Upper Dublin Township.
July 17
DUI checkpoint along Easton Road in Cheltenham Township.